The present invention relates to a technique for manufacturing a semiconductor device and, particularly, to a technique effectively applied to a thermal treatment process of a semiconductor wafer using a RTP (Rapid Thermal Processing).
With scaling-down of the minimum design rule of the semiconductor device, formation of a shallow junction with a depth of, for example, 0.1 μm or less has been demanded. The shallow junction can be achieved by ion implantation of an impurity into a shallow portion of a substrate with using lower acceleration energy. However, after the ion implantation, it is necessary to perform a thermal treatment to the substrate, in order to rearrange the ion-implanted impurity to grid points and activate it or in order to repair the crystal damage caused by the ion implantation.
Therefore, the shallow junction is formed by the ion implantation and the thermal treatment using a single-wafer RTP apparatus with a temperature rising rate of 10° C. or more per second, instead of a batch-type thermal treatment apparatus in which the temperature is increased and decreased relatively slowly. At present, the thermal treatment using the single-wafer RTP apparatus is used also in processes other than the above-mentioned process for forming the shallow junction, and it is expected that such a thermal treatment will be used in various situations in the manufacturing process of the semiconductor device in the future.
In the single-wafer RTP apparatus, a lot of ideas are provided for the method and the apparatus of the thermal treatment to achieve the uniformity in the in-plane temperature of the semiconductor wafer. For example, the method and the apparatus as follows are disclosed (e.g., Patent Document 1). That is, temperature measurement points by a radiation thermometer are set at a plurality of different points where are disposed in an outer peripheral portion of the wafer and in a portion a 70% or more radius away from the wafer, and, simultaneously, the heating is such that the difference in temperature among the plurality of measurement points is controlled within 5° C. in the temperature rising process and during the time when the high temperature is maintained.
[Patent Document 1]
Japanese Patent Laid-Open No. 6-260426